eGFR Calculator in AKI

eGFR in Acute Kidney Injury Equation:

\[ eGFR = 142 \times \min(Scr/\kappa, 1)^\alpha \times \max(Scr/\kappa, 1)^{-1.200} \times 0.9938^{Age} \times (1.012 \text{ if female}) \]

Estimated GFR (eGFR):

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1. What is the eGFR in AKI Equation?

The eGFR in Acute Kidney Injury equation estimates glomerular filtration rate (GFR) from serum creatinine, age, and sex, though it is not recommended for AKI assessment. It uses modified CKD-EPI coefficients specifically for acute kidney injury scenarios.

2. How Does the Calculator Work?

The calculator uses the eGFR in AKI equation:

\[ eGFR = 142 \times \min(Scr/\kappa, 1)^\alpha \times \max(Scr/\kappa, 1)^{-1.200} \times 0.9938^{Age} \times (1.012 \text{ if female}) \]

Where:

\( Scr \) — Serum creatinine (mg/dL)
\( \kappa \) — 0.7 (female) or 0.9 (male)
\( \alpha \) — -0.241 (female) or -0.302 (male)
\( Age \) — Age in years
1.012 — Female multiplier

Explanation: This equation adapts the CKD-EPI formula with different coefficients for acute kidney injury assessment, though its use in AKI is not recommended.

3. Importance of eGFR Calculation in AKI

Details: While this equation provides eGFR estimation in AKI settings, it's important to note that traditional eGFR equations have limitations in acute kidney injury due to rapidly changing creatinine levels and non-steady state conditions.

4. Using the Calculator

Tips: Enter serum creatinine in mg/dL, age in years, and select gender. All values must be valid (creatinine > 0, age between 1-120). Note that this calculation is for reference only in AKI scenarios.

5. Frequently Asked Questions (FAQ)

Q1: Why is this equation not recommended for AKI?
A: eGFR equations assume steady-state creatinine levels, which are often not present in acute kidney injury where creatinine levels change rapidly.

Q2: What should be used instead for AKI assessment?
A: For AKI, serial creatinine measurements, urine output monitoring, and clinical assessment are more appropriate than single eGFR calculations.

Q3: How does this differ from standard CKD-EPI?
A: This equation uses different coefficients (142 vs 141, -1.200 vs -1.209, different alpha values) specifically modified for AKI scenarios.

Q4: When might this calculation be useful?
A: It may provide reference values in research settings or when comparing baseline to acute kidney function, but clinical decisions should not rely solely on this calculation.

Q5: What are the limitations in AKI?
A: Limitations include non-steady state conditions, variable muscle mass, and the lag time between renal injury and creatinine elevation.